One of the movie's producers contacted frontman Jeff Tweedy after noticing a SpongeBob air freshener hanging from his rearview mirror in a scene from the band documentary I Am Trying to Break Your Heart. Tweedy got turned on to the SpongeBob TV show by his sons Spencer, 8, and Sam, 4.

"I fell in love with SpongeBob when I heard him describe the darkness at the bottom of the sea as 'advanced darkness,'" Tweedy says. "How could I not write a song for this film? It automatically makes me the coolest dad on the block."

"Just a Kid" also makes young drummer Spencer the coolest kid on the block, as his band the Blisters accompany Wilco on the song. Tweedy the elder reports that early returns from a dad's toughest critic are positive: "My son's band thinks it rocks."